Arrangement of ship-rudders.



P0. ARRANGEMENT 0F SHIP RUDDERS. APPLICATION FILED AUG-l0, 1915.

3m 0s Wm NE 1% 2 n M Di ARRANGEMENT 0F SHIP RUDDERS. APPLICATION men AUG-l0. 1915.

Patented Nov. 20, 191?.

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GUIDO PO, 015 ROMEITALY.

ARRANGEMENT 0F SHIP-RUDDERS.

Patented Nov. 20, 192W.

Application filed August 10, 1915. Serial No. 44,823.

To all whom it may concern:

Be it known that I, GUmo Po, a subject of the King of Italy, resident at Rome, in the Kingdom of Italy, have invented certain new and useful Improvements in the Arrangement of Ship-Rudders, of which the following is a specification, reference being had therein to the accompanying drawings.

The present invention refers to certain improvements in the arrangement of rudders of ships the object of which is to better the latters evolutional qualities,'to brake same and to reduce head-way when stopping and to lessen the danger ensuing from rudder damages in navigation. By these improvements, dangers of collision or stranding may, in the majority of cases, be avoided or at least diminished.

To properly understand the following description, reference must be had to the annexed drawings, in which Figure 1 shows the evolution curves of a ship steered by the means it at present. has at disposal when maneuvering with the view of avoiding an obstacle. i

Fig. 2 is the side elevation of a ship provided with two rudders placed both in the middle plan.

Fig. 3 is a plan of the same ship.

Fig. 4: shows how without varying the usual arrangement of the stern rudder, a second rudder, according to the present invention, can be added to a merchant ship.

The great maritime disasters of these last few years have led to the adoption of various life saving provisions on board ships. Among the more important and recent provisions made compulsory by the regulations in force with vessels of all marines may be enumerated the following: collision bulkhead with sliding doors controlled from the upper decks radiotelegraphy plant suited to the type of ship; provision of an ade quate number of life boats for the whole of the crew and the passengers.

All these provisions, however, come into operation only after the collision or strand ing, and consequently are only designed to mitigate the latters, efiects. None of any such provisionswith the exception perhaps of the radiotelegraphyaims at avoiding or diminishing the possibility of similar disasters.

It is accordingly very desirable to provide means for preventing disasters of the above nature, and such means might consist in the adoption of steering and controlling apparatus of such nature as to better not only the evolutional qualities of the ship but also to cooperate in braking same and reducing headway on the sudden ap pearance of danger ahead, as well as to render the consequences of rudder damages less dangerous during navigation.

The purpose of the arrangements forming the object of the present invention is to improve the efliciency of steering means mainly for the objects above alluded to.

For instance, in the case of merchant vessels:

These have almost all one single stern rudder of limited dimensions and are provided with a single steering gear. It thus follows that their evolutional qualities are deficient, and further that any damage incurred to their sole rudder, or to its steering-gear may, in certain conditions of weather or in certain latitudes, mean arising of serious danger for the ship itself.

Coming now to the effects of the rudders maneuver in the case of imminence of stranding or collision, let a ship a- (Fig. 1) be navigating at a given velocity in the direction ab. The vessel suddenly discovers a peril .eat a certain distance on its course. The peril may be from some obstacle, or a ship unexpectedly sighted on the course, or any other danger whatsoever.

Whatever the peril --e, hidden to the last moments by fog, heavy rain, darkness, or other reasons, there being immediate danger of collision, and whatever the course of a with respect to e-, the ship awill seek in every possible way to avoid the catastrophe, and according to the space available will try to execute one of the following maneuvers:

(1)Toadvance with the helm all on one side or the other without changing the screws sense of rotation at all.

(2)To immediately reverse the screw motion so as to stop the vessel within the shortest possible distance either (a) by maintaining the same course or (b) by turning on either side, with the helm all to port or starboard. i

In the first case, to which refers the lines -ac, ac of Fig. 1, the maneuver will be convenient when sufficient room for turning is allowed by hydrographic conditions;

so that after an evolution of 90 the curve be reduced during the maneuver if c 7 were a ship advancing toward a' while qualities. 6 5

the maneuver in the second case (Z3), represented in, the figure by the lines -n(l.- ad, the, respective curves of stern and head will be the onegenerally preferred, be-

cause while making sure of the minimum advance onward, it admits alateral displacement on the side most conyenient.

In order t0.be able to accomplish successfullythe above maneuver, ships general, and more particularly IIlQICllfll'llLSlllPS,

must have attained the highest perfection in steering and controlling means, which at present is very doubtful.

In fact, on considering any modern transatlantidflitwill be seen that the same has generally a single rudder, the dimensions of whlchare very small with respect to what they might and should. be. @The normal proportion between the area. of the rudder and the area of the middle .line plane, runs to about 1:50, or 1:60; hiIe there are ships of war, inwhich the finest eyolutional qualities are demanded for tactical reasons, where thesaid proportion rises to 1 30.

This means it is desirable formerchant ships, especially passenger. oats, to greatly increase the size of their rudders. I

,Agarn, on further examlnatlon of modern commercial ships it will b seman the introduction of two or ,tour, turbine screws has led up to a greater difiiculty cutting off the forward movement in stopping,

through the, turbines insufficient power to act with reversed screws.

Summing up, the evolution deficiency in modern commercial ships ensues chiefly from an insuflicient area of rudder, and, from the difficulty of cutting off the forward movement when stopping.

The following arrangements proyide ag i he w i c ve ienr e I iP are furnished, especially those for passenger transport, with two rudders (Figs. 2 and 8) placedon the same -mid- -dle longitudinal plane, one -.s abaft of theother s, theaggregate area of which would beabout one thirtieth ofthemiddle gline; transverse plane of the ship.

With the adoption of the two rudders in the longitudinal, middle plane, the ships [stern must be, a little more sharp than at present, which Will give better 'evolutional This steering area is subdivided between the two rudders placed along the ships longitudinal middle plane as indicated in the -,Figs. 2 and: 3, so that the area of the forward rudder may be about th larger than that of the stern rudder.

The two rudders must be situated at a properdistance from each other so as not to lessen.theirrespective effects; the space from one to the other should be about oneeighth or One-tenthot'Uthe shipls length.

This distance between the .tw ru'ddeie was found to "be theimor'e convenient in respect to the proportions usually adopted. in the constructions of shlps of varloussl jzes'. ,The

action of the rudders isg two foldnamely:

when they are bodily pnt overi'on the same side, they will work together to change the "ships course, while when they are. turned over in opposite directions, their action serves only romance the forward motion of the ship without changing its course. "In order to obtain an efficaciousl action, therudders should not be'situatedtoo ne r the center of. the ship so as notfto unduly" reduce their turning efl' ect. .Atfthe same time, as

explainedbetore, the,'twoirudders must be 7 situated at a suflicient distance one [from the other so" as' not' to influence each, other; F rom the smdiesig'qnfirm u"by'gvario sjexperiments made in thisf. respect it ji esulted that the afore cited .ponditions areinet' in the best possible way 'by, fining asfinterval between the. two rudders a ,distance from to of the shipslength". i When the rudders are put over in opposite directions, it is necessary thatthe'c'ourse of theship 'hekept unchanged. ,Therefore it is necessary that the momentsoit rotation developed by the tworudders be. equall'and of ooposite direction andas, the lever-arm of t 1e stern rudder is longenlthan the leverarm of the. bow-rudder,. 1t s necessaryi that the area of the rudders be n lnverseratio lot. the said arms. As already statedthis is O t n b l v f thh vsnd ef 4 e of larger han th t of t eaters iu' e 3 -These rudders are v provided I .2, 3, and 4) with steering gear with p nde rensmi eieil i fi m. ri h t wm nd r i d ffi whe y m ans b suitable controlling dev ces they can a i y rk ,e the ..seneiiet lrle -bet t gether.

From the same commanders' bridge a transmission allows the :control of gear ]c.. for reyersing, the moyement.

(4 The j rudders are ,arranged so Q that they canghe put all on one sidesimultaneously-in thejsame direction or in opposition;

. the helm angle for both longitudinalrudders instead of being limited, as commonly is at present, to 30 or. 35, berun up to 90 on the two sides (Figs. 2, 3, andA).

(5)A halfbalanced form is, given to the rudders so a o iminis the newer. ass

mamas sary for putting them aside (adopting on a broad line the arrangements indicated by Figs. 2 and 4:.

A ship furnished with the aforesaid apparatus, on suddenly having to avoid a peril ahead, will have a greater chance of escape in executing one of the following maneuvers (1)-Reversing the screws movement and at the same time putting both rudders hard over at an angle of 90 in opposite directions, so as to add to the resistance opposed by the screws reverse motion that constituted by the total area of the rudders.

(2)-Putting both rudders at about or in the same direction on the side proper for getting the maximum turning effect, and for reducing to a-minimum the forward motion of the vessel after 90 of evolution.

(3)Putting the two rudders at an angle of about 30 or on the same side and at the same time reversing the screws movement till the ship stops.

All these measures will have as a result the reduction of the circle in which the ship turns other conditions being equal, to about half the present, and the notable diminution of the course for shutting E the movement. These improved maneuvering qualities Will, in many cases, cooperate to prevent the repe tition of terrible maritime disasters.

It is observed above, that the screws as well as rudder may be controlled by means of suitable apparatus from the commanders bridge. The same does not exclude the screws as well as rudders beingas in fact they are generally controlled also from other parts of the vessel, and especially from the pilots station.

Claims:

1. A ship provided with two rudders placed one behind the other in the middle longitudinal plane, the area of and the distance between the rudders being such as to develop equal and opposite turning moments when set over by equal angles in opposite directions.

2. A ship provided with two rudders arranged at the longitudinal center thereof one in front of the other, the rudders being of half balanced form and the forward one having a greater area that the rear one, and mechanism for operating the rudders, Whereby they may be operated simultaneously or separately and swung into the same or opposite directions.

In testimony whereof I aflix my signature in presence of two witnesses.

GUIDO PO.

"Witnesses An'romo LABoeoU'rTo, RENATO SCEVOLA.

Copies of this patent may be obtained for five cents each, by addressing the Gommissioner of Patents, Washington, I). 0.

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